Iodine monobromide (IBr) at low temperature: A superior protocol for diastereoselective cyclizations of homoallylic carbonates
摘要:
Iodine monobromide (IBr) induces efficient electrophilic cyclizations of homoallylic t-butyl carbonates in toluene or methylene chloride al low temperature, affording significantly better diastereoselectivity than iodine (I2) in acetonitrile.
8-Endo Cyclization of (Alkoxycarbonyl)methyl Radicals: Radical Ways for Preparation of Eight-Membered-Ring Lactones
作者:Eun Lee、Cheol Hwan Yoon、Tae Hee Lee、Sun Young Kim、Tae Joon Ha、Yong-suk Sung、Sang-Hyun Park、Sangyoub Lee
DOI:10.1021/ja980908d
日期:1998.8.1
Cyclization of (alkoxycarbonyl)methyl radicals generated from bromoacetates proceeds in the 8-endo mode to generate heptanolactones. Three distinct types of 8-endo/5-exo tandem radical cyclizations produce different bicyclic heptanolactones. In certain cases, intramolecularfree-radical attack on the heptanolactone carbonyl group initiates further skeletal rearrangement. Ab initio calculations indicate
The successful example of chiral formamides that function as asymmetriccatalysts is described. (S,S)-N,N-Bis(α-methylbenzyl)formamide mediates the enantioselective addition of allyl- and crotyltrichlorosilanes to aliphatic aldehydes with the assistance of hexamethylphosphoramide (HMPA) to afford the corresponding homoallylic alcohols in up to 98% enantiomeric excess.
Double Ring-Closing Metathesis Reaction of Nitrogen-Containing Tetraenes: Efficient Construction of Bicyclic Alkaloid Skeletons and Synthetic Application to Four Stereoisomers of Lupinine and Their Derivatives
作者:Shengming Ma、Bukuo Ni
DOI:10.1002/chem.200305581
日期:2004.7.5
The doublering-closingmetathesisreaction of nitrogen-containingtetraenes was studied. The selectivity of the fused/dumbbell-type products can be controlled by the electronic/steric effects of the substituents attached to the C[double bond]C bonds and the s-cis/s-trans conformational ratios of the substrates. This methodology has also been successfully applied to the enantioselective synthesis of
A stereocontrolled synthesis of the methyl ester of (±)-nonactic acid
作者:Paul A. Bartlett、Karen K. Jernstedt
DOI:10.1016/s0040-4039(00)77765-3
日期:1980.1
Iodine-induced cyclization of a homoallylic phosphate and hydrogenation of a 2,3-dehydrononactic acid derivative are used to introduce the chiral centers selectively in a highly efficient synthesis of methyl nonactate.
[EN] CARDANOL GLYCIDYL ETHER DERIVATIVES<br/>[FR] DÉRIVÉS D'ÉTHERS DE GLYCIDYLE DE CARDANOL
申请人:CT DE TECHNOLOGIE MINERALE ET DE PLASTURGIE INC
公开号:WO2015168771A1
公开(公告)日:2015-11-12
Methacrylated cardanol glycidyl ethers, diglycidyl ethers, intermediates and derivatives thereof are described herein. Compositions and polymers made with such compounds as well as methods of preparation thereof are also described. For example, compounds of Formulas: wherein n, R1, R2, R3, R4, R5, and R6 can each represent various different entities are described in the present disclosure.